Folding window panel



FIG. 1 is a perspective view of a folding window panel in accordance with the present design;

FIG. 2 is front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view;

FIG. 7 is a right side view; and,

FIG. 8 is view showing the folding window panel in a folded configuration.

The broken line elements in the figures form no part of the claimed design. 

CLAIM The ornamental design for a folding window panel, as shown and described. 